This cauliflower gratin is rich, cheesy, and comforting. It's the perfect alternative to potato gratin. It's ready in 30 minutes, and the combination of sour cream, Dijon mustard, gruyere, and parmesan is marvelous.

As versatile as potatoes, cauliflower readily absorbs the richness of cream and cheese. It is thus elevated from a veggie into a true delicacy. Of all the many delicious ways to prepare cauliflower (including mashed cauliflower and cauliflower steak), this creamy gratin is one of my favorites. Granted, adding sour cream and gruyere cheese to almost anything would make it taste good! But this is especially true for cauliflower.
Ingredients and Substitutions
See the recipe card for exact measurements. Here are my comments on some of the ingredients.
- Fresh cauliflower florets: Frozen cauliflower works, too, but fresh is better in terms of flavor and texture.
- Sour cream: I experimented with whole-milk Greek yogurt and thought it was too tangy.
- Mustard: I use Dijon mustard, which is creamier and less vinegary than yellow mustard.
- To season: Salt and pepper. Sometimes, I add a pinch of cayenne and a pinch of dried thyme.
- Grated Gruyere cheese: This wonderfully nutty cheese is amazing. You can also use Jarlsberg or Raclette. Even a mild cheddar will work in a pinch.
- Grated Parmesan cheese: Make sure you use finely grated Parmesan and not coarsely shredded.
Instructions
The detailed instructions and step-by-step photos are included in the recipe card. Here's a quick overview.
Microwave the cauliflower. You should only microwave it until it's tender-crisp. You don't want it mushy.
Mix the microwave-steamed cauliflower with a rich but quick sauce of sour cream, Dijon mustard, grated cheese, and spices. Transfer the mixture to a greased baking dish.
Bake the gratin until golden and fragrant, for about 10 minutes in a preheated 425°F oven. If your baking dish is broiler-safe, you can finish the dish by briefly broiling it to get the top nicely browned.
Recipe FAQs
No. A gratin is a baked casserole prepared in a shallow baking dish. It's topped with a topping (a "crust," hence the name "gratin") that gets browned when baked. The topping typically includes butter, cheese, and/or breadcrumbs.
So, gratin is a baked dish. The idea is to have a browned topping, which can only be achieved by baking or broiling, not microwaving. But you can use the microwave to reheat the leftovers!
You can use broccoli. It's excellent, although the broccoli has a stronger flavor, so the dish is not as similar to a potato gratin as one made with cauliflower.
Yes, although fresh does taste better and has a better texture. Defrost it according to the package instructions, taking care not to overcook it, and drain it thoroughly.
You can keep the leftovers in an airtight container in the fridge for up to 4 days. Reheat them covered in the microwave at 50% power. I don't recommend freezing this gratin.
Serving Suggestions
Since I use a 425°F oven to make this gratin, I like to serve it with a main dish I can cook in the same oven. So, I often serve it with one of the following main dishes:
Recipe Card
Creamy Cauliflower Gratin
Video
Ingredients
- 1 teaspoon butter - for pan
- 1 pound cauliflower florets
- 1 cup sour cream
- 1 teaspoon Dijon mustard
- 1 tablespoon fresh garlic - minced
- ½ cup Gruyere cheese - grated; 50 grams
- 1 teaspoon Diamond Crystal kosher salt - or ½ teaspoon of any other salt, including Morton kosher salt
- ½ teaspoon black pepper - freshly ground
- 2 tablespoons Parmesan cheese - grated
Instructions
- Preheat the oven to 425°F. Grease a shallow 1.5-quart baking dish with butter or olive oil.
- Place the cauliflower florets in a large microwave-safe bowl. Add a tablespoon of water. Cover with a microwave-safe plate and microwave on high until tender-crisp, 5-7 minutes.
- Meanwhile, in a large bowl, mix together the sour cream, mustard, garlic, gruyere, salt, and pepper.
- Drain the cooked cauliflower well (be careful, the bowl will be hot) and pat it dry. Add it to the sour cream sauce, gently tossing to combine.
- Transfer the mixture to the prepared baking dish. Sprinkle the parmesan on top.
- Bake the gratin until heated through, for about 10 minutes. Serve immediately.
Notes
- If your baking dish is broiler-safe, you can switch the oven to broil after the gratin is done and broil it for 1 minute to brown the top. Keep a close eye on it so that it doesn't burn.
- To use frozen cauliflower, defrost it according to the package instructions, taking care not to overcook it, and drain it thoroughly.
- You can keep the leftovers in an airtight container in the fridge for up to 4 days. Reheat them covered in the microwave at 50% power. I don't recommend freezing the leftovers.
Nutrition per Serving
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Disclaimers
Most recipes are low-carb and gluten-free, but some are not. Recommended and linked products are not guaranteed to be gluten-free. Nutrition info is approximate. Please verify it independently. The carb count excludes non-nutritive sweeteners. Please read these Terms of Use before using any of my recipes.